Painting a Layer Mask

I was recently processing a bunch of pictures that I took of this couple for their engagement photos. Painting layer mask after layer mask, I thought, I need to write a tutorial on this.

Painting layer masks is something that I do a lot.It allows you to break the image down into zones and give those zones different treatments. Sometimes it's color, or contrast, or saturation, or maybe some selective blurring. Whatever the reason, being able to paint layer masks is really helpful.

So here we have a pretty decent shot of this young couple. There are a few things that I know I want to do to it right away. I want to bring the background down a bit. I think it's a little overexposed. I also notice that their complexions are very different. She's on the yellow side, he on the magenta. So, right from the start I know that I want at least two layer masks: one for the background, and one for him, to make him more yellow so that his skin tone matches hers better.

NOTE: In this tutorial I'm assuming that I don't have to explain to you the mechanics of layer masks in any detail. If you don't understand how layer masks work, or you get confused partway through this tutorial, you might want to check out our Layer Masks Mechanics tutorial.

And here's the result. While the background is OK, the couple is way too dark. We need to selectively remove the affect of the curves adjustment layer from the couple. We do this by painting a layer mask.

When we added the curves adjustment layer, this is what happened to our layers palette. We have a new layer. You see the half white/half black circle indicating that it's and adjustment layer. There's a box filled with white which indicates the layer mask. Remember, white reveals, black conceals. So the parts of the mask that are white will reveal the affects of that adjustment layer, and the parts that are black will conceal.

Right now the entire mask is white. This is right in keeping with the fact that the entire image is being affected by the curves adjustment that I made.

Select the brush tool, and make sure you set the hardness to 0%. You can adjust the Master Diameter to suit. Make it big enough to be convenient, but not so big that it's unwieldy. The size completely depends on the resolution of the image and the size of the area you want to paint. But always 0%.

While you're viewing the red overlay of the layer mask, you can hit "`" (tilde) (this is the key next to the number 1, and above the TAB key on most keyboards), which will hide the "RGB" layer (which holds the color information of the image) and show you just the mask. This is really helpful for finding parts of the mask that you missed. Toggle back and forth by hitting "`" until you're happy. When you're done, hit backslash again, and the layer mask will disappear. If you were only viewing the layer mask, as in the image here, then you'll be popped back into RGB mode, and see just the image.

And this is what we get. We've restored the couple, but kept the curves adjustment on the background.

You'll notice that I didn't have to obsess on the selection. you don't need to worry about every nook and cranny of the image. With a hardness of 0% and a sufficiently large brush the border is soft enough that you just can't see it.

When you control click, you put a marker in the curve. A handle, that you can adjust the curve with. Just use your up and down arrows to adjust. In this case, we want to make the blue darker, which will increase the yellow in the image, so we'll use the down arrow.

This is what our layers palette looks like. Oh, dang, we didn't label our layers. We'll get to that soon. Remember to label layers so that they make sense if you ever go back to work on the image at a later time.